如何压缩asm.js编译消息？

Question

When using asm.js code some browsers emit a compilation message. This one:

Successfully compiled asm.js code (loaded from cache in 201ms)

Is there a way to suppress this message?

Answer 1

The message itself is here: https://hg.mozilla.org/mozilla-central/file/tip/js/src/js.msg#l357

 MSG_DEF(JSMSG_USE_ASM_TYPE_OK, 1, JSEXN_WARN, "Successfully compiled asm.js code ({0})") 

And it is emitted here: https://hg.mozilla.org/mozilla-central/file/tip/js/src/wasm/AsmJS.cpp#l8718

 static bool SuccessfulValidation(AsmJSParser& parser, UniqueChars str) { return parser.warningNoOffset(JSMSG_USE_ASM_TYPE_OK, str.get()); } 

Which is called here: https://hg.mozilla.org/mozilla-central/file/tip/js/src/wasm/AsmJS.cpp#l8877

  // Success! Write to the console with a "warning" message. *validated = true; SuccessfulValidation(parser, Move(message)); return NoExceptionPending(cx); } 

There is no apparent "optionality" in that line, even the comment says that it is going to the console, period.

Otherwise JSEXN_WARN has a couple real occurrences only (in jsexn.h , jsexn.cpp and in jsapi.h ), the latter one descibes it as it is practically an exception type which does not break execution and does not have a scary part ("Error:..."): https://hg.mozilla.org/mozilla-central/file/tip/js/src/jsapi.h#l580

 * JSEXN_WARN is used for warnings in js.msg files (for instance because we * don't want to prepend 'Error:' to warning messages). This value can go away * if we ever decide to use an entirely separate mechanism for warnings. 

And it is true, most checks for JSEXN_WARN are about skipping the throw of an actual exception, in a if ( ... || exnType == JSEXN_WARN || ... ) do nothing fashion, like here (just one, ad-hoc example).

I am not sure what you really need, but

How to supress asm.js compilation message?

Via building your own copy of Firefox: https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Simple_Firefox_build